The present invention broadly relates to a new and improved construction of papermaking machine.
In its more specific aspects the invention relates to a new and improved papermaking machine comprising an endless water pervious inner dewatering band which extends or wraps with its inner side or surface around at least two series or successively arranged sections of dewatering surfaces. In each wrap-around section thus formed the inner dewatering band is convergently guided or brought together with a respective portion of an endless water pervious outer dewatering band. The infed portion of the outer dewatering band is supplied or infed via an infeed element, and a substantially wedged-shaped infeed throat or gap is thus formed. A dewatering section follows the infeed throat or gap and at that location the outer dewatering band is guided along the outer side or surface of the inner dewatering band. The outer dewatering band is then returned towards the infeed throat or gap by deflecting means. The papermaking machine further comprises at least two stock infeed devices, namely headboxes for forming at least two fiber webs or plies which are to be joined. Each of the headboxes is directed towards a related infeed throat or gap.
In a papermaking machine of this kind as known, for example, from German Patent Publication No. 3,117,463, the series arranged or successive dewatering surfaces are formed at separate rollers. The known arrangement requires a relatively large installation length for the successive headboxes. This is particularly true in designs intended for fabricating a fiber web or ply which comprises more than two layers.